Nestable container

ABSTRACT

A nestable container of thin wall plastic construction having a stacking protuberance in the bottom thereof to limit the extent of telescopic association of adjacent containers. The stacking protuberance comprises a lower stacking shoulder of generally circular configuration, an upper stacking shoulder having an odd number of lobes numbering at least three extending radially outwardly a distance greater than the radius of the lower stacking shoulder, and an intermediate side wall connecting the upper stacking shoulder and the lower stacking shoulder, said side wall having an inclination which varies about the periphery of the protuberance between a convergent angle and a divergent angle with respect to the container axis.

1451 Oct. 1, 1974 NESTABLE CONTAINER [75] Inventors: Theo 0. Lang;Thomas H. Eyles,

both of Leominster, Mass.

[73] Assignee: Foster Grant Co., Inc., Leominster,

Mass.

[22] Filed: July 30,1970

21 Appl. No.: 59,416

[52] US. Cl. 206/520 [51] Int. Cl B65d 21/02 [58] Field of Search 220/97C; 229/15 13; 206/520, 519

[56] References Cited UNITED STATES PATENTS 3,347,411 10/1967 Kalata220/97 C 3,442,420 5/1969 Edwards 220/97 C FOREIGN PATENTS ORAPPLICATIONS 2,005,409 12/1969 France 220/97 C 301,596 6/1968 Sweden220/97 C Primary Examiner-George E. Lowrance Attorney, Agent, orFirm-Leonard S. Selman; Leroy G. Sinn 5 7 ABSTRACT A nestable containerof thin wall plastic construction having a stacking protuberance in thebottom thereof to limit the extent of telescopic association of adjacentcontainers. The stacking protuberance comprises a lower stackingshoulder of generally circular configuration, an upper stacking shoulderhaving an odd number of lobes numbering at least three extendingradially outwardly a distance greater than the radius of the lowerstacking shoulder, and an intermediate side wall connecting the upperstacking shoulder and the lower stacking shoulder, said side wall havingan inclination which varies about the periphery of the protuberancebetween a convergent angle and a divergent angle with respect to thecontainer axis.

4 Claims, 5 Drawing Figures ma aanrz SHEET 1 BF 2 INVENTOR- mm o. LANGTHOMAS .H. EYLES ATTORNEYS EAIENI nmr nan A 3.888.772 mum:

NESTABLE CONTAINER BACKGROUND OF THE INVENTION 1. Field of the InventionThis invention pertains generally to nestable thin wall plasticcontainers which incorporate means to prevent adjacent containers in astack from jamming or sticking together, and more particularly tocontainers having such means formed in the bottom thereof.

2. Description of the Prior Art Thin wall plastic containers are widelymanufactured for a variety of uses. The containers are generally bowl orcup shaped, having side walls diverging upwardly from the bottom. Suchcontainers are usually molded and, since they are chiefly one-waydisposable carriers, the thickness of the material used is in the realmof 0.01 inches. Such containers can be jammed together by theapplication of telescopic loads, and are easily deformed and damaged bytelescopic loads and by abusive handling.

Telescopic forces of sufficient magnitude to cause jamming or stickingcan easily be generated during normal manual or automatic handling,thereby inhibiting the removal of individual containers from the top orthe bottom of the stack. In the case of automatic machines, such asdrink vending machines, the consequence of this jamming or sticking canbe the rendering of the machine inoperable. In the case of manualremoval of a container from the stack, jamming and sticking causescontainer damage and waste. Toeliminate this problem, means to separateadjacent containers can be molded into each container. These separatingmeans can be in the area of the rim, side wall, or bottom. One form ofsuch means is a pattern of protuberances molded into the sides or thebottom of the container. The use of protuberances in the side wall of athin wall plastic container renders the outer surface unsuitable for theapplication of printing, and also eliminates the aesthetically pleasingsmooth side wall shape. If the side wall protuberances are inwardlyfacing, a recess is created in the outer surface, and this recesscollects dust and dirt.

An alternative is the use of bottom stacking protuberances. Bottomstacking protuberances of many configurations are set forth in the priorart, as shown in US. Pat. Nos. 2,988,258; 3,027,596; 3,l3l,845; and3,442,420. The protuberance must be operationally effective no matterwhat the relative radial alignment of adjacent containers. For example,a protuberance cannot be of such configuration as to nest with anadjacent protuberance when a telescopic load is applied, thus defeatingtheir purpose.

The protuberance must also be easily molded and removed from the mold.In US. Pat. No. 2,988,258 the concept advanced is the use of at leasttwo different easily moldable configurations of bottom stackingprotuberances so that adjacent containers can be provided withprotuberances of dissimilar configuration. This solves the problems ofnesting of adjacent protuberances, but greatly complicates theoperations of molding and packaging. The other three patents cited aboveutilize bottom stacking protuberances which include an intermediate wallhaving an undercut or back-draft portion connecting the upper and lowerstacking shoulder. Thus, an engaging shoulder is created on the top ofone protuberance to engage the bottom of the adjacent container.However, the use of backdraft angles raises serious problems in themolding operation. Where back-draft angles are radially oppositelyaligned, a pinching action is exerted on the mold portion which formedthe protuberance, thus inhibiting removal of the container from themold. This can increase the wear on the mold, lower the operating speedof the machine, and cause damage to the containers. To solve thisproblem, certain prior art devices utilize a back-draft at a singleportion only of the protuberance, but this is generally unsatisfactory,as discussed below.

It is desirable to distribute the telescopic load evenly upon the bottomof each individual container to prevent the possibility of damage due toforces being concentrated at a single point. If a single back-draft isused, all of the telescopic force is concentrated at a single point,often exceeding the strength of the container at that point or causingthe container to wedge sideways and, if adjacent protuberances happen tobe radially aligned, one protuberance will be forced to nest over theother.

Another consideration in the design of bottom stacking protuberances isto provide minimum intrusion into the volume of the container whilemaintaining the effectiveness of the protrusion to prevent jamming andsticking. It is also desirable for the protuberance to be aestheticallypleasing, as well as not interferring with implements used to remove thecontents from the container.

The bottom stacking protuberances set forth in the prior art, asexemplified by the cited patents, fall short of solving the problemsenumerated above.

SUMMARY OF THE INVENTION The invention advanced herein provides a novelbottom stacking protuberance which eliminates or greatly reduces theeffects of the abovementioned problems. A thin wall plastic containermanufactured in accordance with this invention has a side wall extendingupwardly and diverging outwardly from a bottom into which is installed astacking protuberance. The stacking protuberance has a lower stackingshoulder and an upper stacking shoulder, both disposed symmetricallyabout the container axis. The upper stacking shoulder describes an oddnumber of radially outwardly extending lobes numbering not less thanthree. The upper stacking shoulder can also form the periphery of anupper surface parallel to the container bottom. A protuberance wallconnects the lower stacking shoulder and the upper stacking shoulder. Atthe outer portions of the lobes, the upper stacking shoulder extendsoutwardly from the container axis a radial distance greater than thatportion of the lower stacking shoulder which is radially alignedtherewith, preferably by a degree of at least the thickness of materialof which the container is formed. This creates an engaging portion onthe upper stacking shoulder and the upper surface which will engage thebottom of an adjacent protuberance, and which will exist even ifadjacent protuberances are of identical radial alignment. Theprotuberance wall varies in inclination with respect to the containeraxis about the periphery of the upper stacking shoulder, and isdivergent with respect to the container axis at each of the engagingportions of the lobes. Therefore, the protuberance wall has a back-draftportion at each upper stacking shoulder lobe.

Removal of a container constructed in accordance with this inventionfrom the mold is facilitated by the novel arrangement of back-draftportions so that they are not directly opposed, thereby allowing thecontainer to easily and safely deform as necessary during removal fromthe mold without damage and without the application of a highlevel offorce.

Telescopic forces placed upon containers constructed in accordance withthis invention are distributed symmetrically over a large portion of thebottom of the container, thus preventing sideward shifting of thecontainer under telescopic load and lessening the chance of damage.Since a plurality of symmetrical engaging portions is provided by thisinvention, nesting of protuberances of identical radial alignment underthe influence of telescopic loads is precluded.

It is an object of this invention to provide a thin wall containerhaving a novel bottom stacking protuberance that prevents adjacentcontainers from jamming or sticking together under the influence oftelescopic loading.

Another object of this invention is to provide a thin wall containerhaving a novel bottom stacking protuberance that facilitates removal ofthe container from the mold.

Another object of this invention is to provide a thin wall containerhaving a novel bottom stacking protuberance that distributes telescopicloads symmetrically over a large portion of the bottom of the container.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspectiveview showing a seamless thin wall plastic container having a bottomstacking device in accordance with the present invention;

FIG. 2 is a top view of the container of FIG. 1;

FIG. 3 is a cross-sectional view taken through line III- III of FIG. 2;

FIG. 4 is a cross-sectional view of the relationship of protuberances ofadjacent containers constructed in accordance with this invention; and

FIG. 5 is a top view of another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION The general form of cup orcontainer 10, which incorporates the bottom stacking means of thepresent invention, is illustrated in FIGS. 1-3 of the drawings.Container is of a seamless thin wall construction molded from athermoplastic material such as polystyrene, and formed into afrustoconical shape including a bottom 12 and a peripherially continuousside wall 14, which diverges upwardly and outwardly from bottom 12 andterminates in a rim portion 11. The container illustrated is an exampleonly, for the bottom stacking protuberance herein set forth can beutilized equally well with containers of other shapes and of othermaterials.

A novel stacking protuberance 18 is integrally formed into bottom 12 byconventional thermoforming techniques. As best illustrated in FIG. 3,stacking protuberance 18 comprises a lower stacking shoulder 13, anupper stacking shoulder axially spaced from lower stacking shoulder 13,and a protuberance connecting wall section 16. Although stackingprotuberance 18 is illustrated as being inwardly directed, it

could also be outwardly directed within the scope of the invention.

Lower stacking shoulder 13 is in the plane of bottom 12, and issymmetrically disposed about container axis 17. Lower stacking shoulder13 is illustrated as having a circular configuration of radius Rl, butother configurations can be used within the scope ofthis invention.

The upper stacking shoulder 15 is advantageously in a plane parallel tothe plane of bottom 12, and describes a plurality of lobes 21. In thepractice of this invention, lobes 21 can be of any odd number not lessthan three. Upper stacking shoulder [5 lies about the periphery of anupper surface 20, which can be in the same plane thereas. Portions ofupper stacking shoulder 15 extend radially outwardly beyond that portionof lower stacking shoulder 13 radially aligned therewith. In the case ofa circular lower stacking shoulder 13, these portions of upper stackingshoulder 15 extend outwardly a radial distance greater than Radius R1,and an engaging portion 22 which contacts the bottom of an adjacentcontainer is defined on surface 20 upper stacking shoulder 15. Upperstacking shoulder 15 also describes indented portions 19 spacing each oflobes 21 from one another. Indented portions 19 are of lesser or equalradius than lower stacking shoulder 13 radially aligned therewith. Themaximum radial distance R2 from axis 17 to upper stacking shoulder 15 atengaging portions 22 preferably exceeds that of the radially alignedpoint of lower stacking shoulder 13 by at least the thickness of thematerial from which the container is constructed. This insures thepresence of sufficient overlap between the protuberance of adjacentcontainers to prevent nesting of adjacent protuberances. In thisembodiment, as shown in FIG. 2, surface 20 is configured somewhat like athree leaf clover. However, it is not necessary that lobes 21 be threein number, but

only that an odd number of lobes, not less than three, be utilized. Thelobes can be arcuate or of other configuration, such as the one shown inFIG. 5.

Lower stacking shoulder 13 is illustrated as being of circularconfiguration, but that is not a necessity. The chief requirement isthat the radial distance R2 of upper stacking shoulder 15 at engagingportions 22 must exceed the radial distance R1 of that portion of lowerstacking shoulder 13 which is radially aligned therewith. The remainderof the periphery of upper stacking shoulder 15 is of radial distanceless than or equal to the radial distance of the respective radiallyaligned portion of lower stacking shoulder 13.

A protuberance side wall 16 connects upper stacking shoulder 15 andlower stacking shoulder 13. Since engaging portions 22 are of greaterradial distance from axis 17 than the portion of lower stacking shoulder13 radially aligned therewith, side wall 16 varies in inclinationbetween an angle A diverging from axis 17 at engaging portions 22, andan angle B which converges toward axis 17 at the remainder of theperiphery of upper stacking shoulder 15. Although illustrated asaltemating portions of simple curvature, resulting in a distinct joiningline 23 at each lobe 21, side 16 can be of compound curvature, thuspresenting a continuous smooth line.

The maximum convergent inclination of side 16 will vary depending uponsuch factors as the height of the protuberance and the desire forminimum intrusion into the volume of the container. In the containerillustrated, the maximum convergent angle B is about 37 degrees from thevertical. Portions of protuberance wall 16 not radially aligned withengaging portions 22 can be parallel to, rather than converging upon,axis 17. Thus, as illustrated, angle B can be vertical. As angle A, theback-draft, is increased at engaging portions 22, the area of eachengaging portion 22 is increased. lt is normally desirable to utilize aminimum angle of back-draft, consistant with the design effectiveness ofthe protuberance.

As shown in HQ 4, adjacent containers are prevented from jamming orsticking due to the engagement of a portion of bottom 12a of the uppercontainer a with engaging portions 22 of the lower container 10. Nomatter what the relative radial positioning the lobes 21 of the twoprotuberances 18 and 18a, all of the engaging portions 22 will contactbottom 12a.

Owing to the symmetrical lobular pattern, the upper container 10a issupported at three equally spaced points in a plane parallel to bottom12 no matter what the radial orientation of one container to the other.Thus, loads transmitted from container to container are distributed to alarge portion of the bottom of the container, and are not concentratedat a single area.

Removal from the mold is facilitated by the presence of symmetricalback-draft portions opposite which there is a portion of wall 16 havingno back-draft.

The height of protuberance 18 should be held to a minimum to minimizethe loss of container volume attributable thereto. The height H selectedfor protuberance 18 is dependent upon the divergence of sides 10, thethickness of the material of which the containers are formed, and thedesired separation between the sides 10 of adjacent containers. Sincethe stacking protuberance 18 provided by the instant invention issymmetrical about the container axis 17, telescopic loads will be evenlytransmitted between adjacent containers and the possibility ofcontainers tilting to the side opposite the engaging shoulder under loadis eliminated. Likewise, deformation of the container in one directionand nesting of protuberances over one another is eliminated.

It should be noted that the particular configuration of protuberance 18which is shown in FIG. 2 is not critical to the invention. For example,as shown in FIG. 5, upper stacking shoulder 35 can describe aprotuberance 38 of equilateral triangle configuration having engagingportions 42 at the corners thereof. Protuberance 38 is symmetricallydisposed about the container axis 37. In this configuration, lowerstacking shoulder 33 is also of generally triangular shape. The radialdistance from the container axis 37 to upper stacking shoulder 35 at thecorners exceeds slightly the radial distance to the portion of lowerstacking shoulder 33 which is radially aligned therewith. Engagingportion 42 are thereby created at the corners. In this configurationthere are back-draft angles at each of the engaging portions 42.

The exact configuration of the protuberance can vary greatly within thelimits of the invention. The embodiments set forth above include but twoof the many usable configurations. The number of lobes can also bevaried within the parameters set forth above. Therefore, the inventiveconcept is extremely versatile and can be used with many containertypes, designs, and materials. 7

Obviously, many variations and modifications of the invention describedabove will become obvious to those skilled in the art. However, thescope of the invention is notto be governed by the embodimentsillustrated herein, but is to be determined by the claims.

We claim:

1. In a thin wall plastic container having a bottom and a side wallextending upwardly and outwardly from said bottom, a stackingprotuberance disposed symmetrically about the axis of said containercomprising:

a lower stacking shoulder in the plane of said bottom;

an upper stacking shoulder axially spaced from said lower stackingshoulder and parallel thereto, said upper stacking shoulder describingan odd number of lobes numbering not less than three symmetricallydisposed about said axis;

a protuberance wall connecting said lower stacking shoulder and saidupper stacking shoulder, said protuberance wall having an angle ofinclination divergent in an upwardly direction with respect to saidcontainer axis at the outer portions of each of said lobes to form anengaging portion on each of said lobes to engage the bottom of anadjacent container; and

indented portions of said upper stacking shoulder spacing said lobesfrom one another, said protuberance wall having an angle of inclinationconvergent in an upwardly direction with respect to said container axisat said indented portions which are located diametrically opposite eachof said lobes.

2. A container according to claim 1 wherein said lower stacking shoulderis circular and said lobes and said indented portions are arcuate.

3. A container according to claim 1 wherein said upper stacking shoulderdescribes a substantially triangular configuration, said lobes being thecomers thereof. I

4. A container according to claim 1 wherein said upper stacking shoulderforms the periphery of an upper surface in the plane of said upperstacking shoul-

1. In a thin wall plastic container having a bottom and a side wall extending upwardly and outwardly from said bottom, a stacking protuberance disposed symmetrically about the axis of said container comprising: a lower stacking shoulder in the plane of said bottom; an upper stacking shoulder axially spaced from said lower stacking shoulder and parallel thereto, said upper stacking shoulder describing an odd number of lobes numbering not less than three symmetrically disposed about said axis; a protuberance wall connecting said lower stacking shoulder and said upper stacking shoulder, said protuberance wall having an angle of inclination divergent in an upwardly direction with respect to said container axis at the outer portions of each of said lobes to form an engaging portion on each of said lobes to engage the bottom of an adjacent container; and indented portions of said upper stacking shoulder spacing said lobes from one another, said protuberance wall having an angle of inclination convergent in an upwardly direction with respect to said container axis at said indented portions which are located diametrically opposite each of said lobes.
 2. A container according to claim 1 wherein said lower stacking shoulder is circular and said lobes and said indented portions are arcuate.
 3. A container according to claim 1 wherein said upper stacking shoulder describes a substantially triangular configuration, said lobes being the corners thereof.
 4. A container according to claim 1 wherein said upper stacking shoulder forms the periphery of an upper surface iN the plane of said upper stacking shoulder. 